Humidifier drive

ABSTRACT

A humidifier for a warm air heating system comprises a water pickup drum rotating with its lower sector passing through a body of water, the drum rotor being rotatably mounted on a motordriven shaft and connected to the shaft by a slip clutch that temporarily yields to excess torque between the rotor and shaft, and the clutch comprising a toothed spring element frictionally engaging formations on the side of a hub on the rotor.

United States Patent [151 3,640,515 Stiles 1 Feb. 8, 197 2 [54] HUMIDIFIER DRIVE 3,013,413 12/1961 Luning ,.64/ 15 B X 3,149,626v 9/1964 .....261/92 X [72] Inventor. Walter R. Stiles, Milford, MlCh. 3,285,586 1 1,1966 "ms/232 x [73] Assignee: Shuttle Manufacturing Company, Milford, 3,408,880 1 1/ 1968 Stiles ..261/92 UX Mich. FOREIGN PATENTS OR APPLICATIONS [22] FIIed: Feb. 13, 1968 200,046 11] 1955 Australia ..64/15 H [21] Appl. No.: 705,184

Primary Examiner-Frank W. Lutter 52 us. CL ..261/92, 55/234, 64/29 Assisi! ExaminerB=mard Nozick 51 mg I 24 3 14 Attarney-Strauch, Nolan, Neale, Nies & Kurz [58] Field of Search ..261/92; 64/15 B, 29; 55/232,

55/234 ABSTRACT A humidifier for a warm air heating system comprises a water [56] References cued pickup drum rotating with its lower sector passing through a UNITED STATES PATENTS body of water, the drum rotor being rotatably mounted on a motor-driven shaft and connected to the shaft by a slip clutch 902,623 1 H1908 Subert .261/91 X th t t rarily yields to excess torque between the rotor and 5 85 1946 wfflff 1 X shaft, and the clutch comprising a toothed spring element fric- 2,583J95 1/1952 wllcox v "261/92 tionally engaging formations on the side of a hub on the rotor. 2,631,831 3/1953 Robic .261/92 X 2,861,437 11/1958 Bachman ....64/ 15 B 13 Claims, 12 Drawing Figures irrz agfsizi* agiifaiaaa PAIENIEUHB 8 I972 3.640.515

sum 1 BF 3 lNVE/VTOR WALTER R. ST/LES M m M WZar/ WM,

ATTORNEYS HUMIDIFIER DRIVE BACKGROUND AND SUMMARY OF INVENTION This invention relates to drive mechanism for rotary-type humidifiers and it is particularly concerned with such mechanism wherein the drive connection to the rotor is automatically protected from injury due to excessive torque while the excess torque conditions prevail. Rotary humidifiers are known wherein the slowly turning rotor carries a removable sleeve of open pore material such as foamed polyurethane that picks up water from a reservoir during part of its revolution and permits evaporation of that water into a hot airstream during the remainder of the revolution. The invention is primarily directed to an improvement in such rotary humidifiers.

The rotor is driven by a low-power electric motor through a considerable drive reduction gear train to obtain very slow speeds of rotation of the rotor. It has been found that under some operational conditions, such as where the rotor becomes difficult to start turning due to crusted or accumulated deposits or when the sleeve is being removed from or replaced on the rotor in the assembly, the drive gearing may be accidentally stripped because of unintentionally applied excess torque. Also where some of the gearing is exposed within the humidifier casing it may be subject to rust or corrosion.

The invention prevents such injury to the drive gearing in such rotary humidifier by providing a special slip clutch between the rotor and a shaft on which the rotor is rotatably mounted, the clutch having the capacity of transmitting normal starting and driving torques but being adapted to slip to interrupt power transmission when the torque exerted either by the motor trying to rotate the rotor, or by a person changing the rotor sleeve, becomes in excess of that for which the reduction gears are designed, and it is the major object of this invention to provide the foregoing. The invention contemplates a novel arrangement wherein the rotor is rotatably supported on a driven shaft that is directly coupled to the reduction gearing output shaft and a slip clutch directly connects the driven shaft and the rotor. A special form of slip clutch includes coacting clutch element in the form of a hub on the rotor and a toothed spring arm on the driven shaft axially engaged in torque transmitting arrangement. These and other features as will appear are further objects of the invention.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a side view partly broken away and in section showing a humidifier incorporating a rotor drive according to a preferred embodiment of the invention;

FIG. 2 is a fragmentary view partly in section showing a detail substantially on line 2-2 of FIG. 1;

FIG. 3 is a side elevation partly broken away and sectioned showing the rotor and associated drive apart from the housing;

FIG. 4 is an end view of the assembly of FIG. 3;

FIG. 5 is an enlarged fragmentary view partly in section showing the clutch connection between the rotor and the shaft;

FIG. 6 is a section substantially on line 6--6 of FIG. 7 showing the rotor hub at the end opposite to the drive connection end;

FIG. 7 is a side view of the rotor hub of FIG. 6;

FIGS. 8-10 are side, front and end views of the clutch spring clip element in the drive; and

FIGS. 11 and 12 are end and side views respectively of the clutch hub.

PREFERRED EMBODIMENTS A rotary water pickup drum 1] is supported on a horizontal drive shaft 12 rotatably mounted within a housing 13. The drum comprises a wire frame 14 carrying on its periphery an endwise removable annulus 15 of open pore polyurethane or equivalent the lower section of which continuously moves through a body of water suitably maintained at a constant level within a pan 16 in the bottom of the housing. Housing 13 has an air inlet 17 and an air outlet 18.

At one end shaft 12 is mounted within a bore 19 of a coupling collar 21 having an inner end radial slot 22 through which shaft 12 extends. A pin 23 is fixed on shaft 12 within slot 22 to provide a detachable drive connection between the collar and driven shaft.

An electric motor unit assembly 24 has its casing secured to the housing sidewall as by fasteners 25 and an output shaft 26 projects from a reduction gear section 27 of the assembly through the housing wall into collar bore 19 where it is secured to the collar as by setscrew 28. Motor unit section 27 contains the train of reduction gearing necessary to obtain the desired low speed of driven shaft 12. One end of the rotor 1 1 is thus supported by the output shaft of the motor unit 24.

At its other end shaft 12 is rotatably supported within an upwardly open slot 29 of a bearing element 31 suitably fixed to a cross strap 32 rigid with the housing and bridging inlet 17.

Rotor frame 14, as shown best in FIGS. 3 and 4, comprises one imperforate end member 33 having a central hub 34 formed with a bore 35 rotatably surrounding cylindrical shaft 12. A radial stop flange 36 is fixed on shaft 12 to abut the outer end of hub 34, and the inner end of hub 34 is abutted by a freely rotatably washer 37 axially restrained by radial shaft projections 38. Preferably the hub bore is enlarged at both ends as shown to reduce the bearing area of the support of frame 14. The foregoing structure mounts frame 14 freely rotatably on shaft 12 and limits axial displacement of the frame along the shaft.

Frame 14 comprises a cylindrical periphery formed by circumferentially spaced selectively stiff wire rods 41 having their ends at one side fixed in sockets 42 in end member 33. As shown rods 41 are parallel to shaft 12 and at their inner ends are turned in at right angles to form radial spokes 43 that thrust rigidly into radially open sockets 44 of a rotor hub 45.

Rotor hub 45 is composed of two stamped sheet metal parts fixed together in opposed relation to form a central body portion 46 having a bore 47 to rotatably receive shaft 12, and to form a series of mainly cylindrical surface bosses 48 that are equally spaced circumferentially and define the open ended sockets 44. As shown in FIG. 5, the body of rotor hub 45 is axially confined between a shoulder 49 on the shaft 12 on one side and a freely rotatable washer 50 backed by a series of shaft projections 51 on the other side but this does not impede relative rotation of the hub and shaft.

Thus the rotor is freely rotatably supported and axially limited against displacement at opposite ends on driven shaft 12 which is connected to be driven at a suitable low speed by motor unit 24.

At the opposite end from member 33, the open end of the rotor is drive connected to shaft 12 by a releasable spring clutch assembly 52 comprising a clutch hub 53 fixed to shaft 12 as by setscrew 54 and a toothed spring clutch element 55 that engages rotor hub 45.

Clutch hub 53 is formed with a bore 56 to receive shaft 12 and at its inner side with a flat radial face 57 perpendicular to the shaft axis. Beyond face 57 the hub is formed with an axially short noncircular portion 58 having flat sides and a reduced diameter axial projection 59 that preferably carries shoulder 49.

Spring clutch element 55 is U-shaped and formed from a strip of spring steel with a central noncircular flat-sided opening 61 adapted to fit snugly and nonrotatably upon the hub portion 58 flush upon face 57. At opposite ends clutch element 55 is formed with clutch teeth 62 that extend substantially parallel to the shaft axis and have rounded ends 63 that in the assembly resiliently frictionally engage the outer side surface of rotor hub 45 circumferentially between two adjacent bosses 48.

In assembly, clutch hub 53 is pushed to the left in FIG. 5 until the clutch teeth 62 positively engage rotor hub 45 between a pair of bosses 48 and clutch element 55 is under slight axial compression before set screw 54 is tightened.

During normal operation, motor unit 24 rotates shaft 12 slowly, usually about four revolutions per minute, and water picked up by the rotating annulus becomes entrained in the air passing through the housing. During such normal rotation the resilient clutch engagement of element 55 with rotor hub 45 transmits the required torque and there is no relative rotation between the rotor and shaft 12.

However, should the occasion arise where the torque to be transmitted to the rotor exceeds an amount that may be damaging to the reduction gears in the motor unit, as where the pores of annulus 15 have become blocked with deposits from the water and the annulus increases in weight, the slip clutch permits relative rotation between the shaft and rotor to protect the gears. This relative rotation is permitted when the torque exceeds a predetermined amount, by teeth 62 camming over bosses 48 as permitted by the resiliency of the clutch element 55. Thus no matter what the direction of relative rotation between the rotor and shaft, the clutch is not impaired and the. teeth 62 merely shift to a new position between an adjacent pair of rounded boss surfaces 48. The entire rotor and shaft assembly is removed by tilting the right end of shaft 12 upwardly in FlG.'1 and at the same time pulling it slightly to the right to remove its left end from bore 19. Thus it is not necessary to disengage the clutch to remove the rotor for treatment or renewal of the annulus 15, and all clutch parts may be left in normally operative condition. Should the torque between the shaft and rotor be accidentally increased while the shaft is being removed, the clutch will slip and there will be no damage to the motor gears.

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

What is claimed and desired to be secured by Letters Patent 1. In a humidifier assembly of the type wherein a rotatable water pickup rotor drum comprising a support frame and a porous annulus mounted thereon has a lower portion extending into means containing a body of water, rotor support shaft means mounted for rotation about an axis, means rotatably mounting opposite ends of said rotor support frame on said support shaft means so that said rotor drum may be bodily rotated upon and around said support shaft means, drive means comprising an electric motor and reduction gearing having an output shaft distinct from said support shaft means connected for rotating said support shaft means, and slip clutch means interconnecting said support shaft means and rotor support frame for normal rotation together comprising cooperating directly engaged clutch elements on the rotor support frame and support shaft means respectively, said clutch elements being so constructed and arranged as to slip to interrupt normal drive engagement when torque between the support shaft means and rotor support frame exerted in either direction exceeds a predetermined amount and to automatically assume normal drive engagement when said torque is less than said predetermined amount.

2. in the humidifier assembly defined in claim 1, said shafts being connected by axially separable positive coupling means.

3. In the humidifier assembly defined in claim 1, said output shaft being connected to one end of said support shaft means, and said slip clutch means connecting said rotor support frame to the other end of said support shaft means.

4. In the humidifier assembly defined in claim 1, said rotor support frame comprising at one end a hub structure having a plurality of circumferentially spaced clutch formations providing the clutch element on saidrotor support frame, and the clutch element on said support shaft means comprising a spring arm assembly nonrotatably secured on the support shaft means and having clutch formations coacting with those on the rotor support frame.

5. In the humidifier assembly defined in claim 4, said spring arm assembly consisting essentially of resilient metal strip means having rounded clutch formations projecting into engagement with the rotor support frame hub.

6. In the humidifier assembly defined in claim 1, said clutch elements being respectively a hub on the rotor support frame and a resiliently biased clutch part on the support shaft means engaging said hub.

7. In the humidifier assembly defined in claim 6, said hub having a plurality of circumferentially spaced lateral projections and said clutch part having laterally projecting teeth frictionally engaging the hub between an adjacent pair of said projections.

8. in the humidifier assembly defined in claim 6, said clutch part being a spring arm nonrotatably mounted on the support shaft means and having its opposite ends bent to form said hub engaging teeth.

,9. in the humidifier assembly defined in claim 1 said rotor support frame having a hub rotatably surrounding said support shaft means, circumferentially spaced lateral formations on said hub providing one of said clutch elements, and the other of said clutch elements being a spring arm fixed to said support shaft means and having opposite end projections frictionally engaging said hub between said formations.

10. In the humidifier assembly defined in claim 9, said formations being rounded and said arm projections having rounded ends engaging the hub.

11. In the humidifier assembly defined in claim 1, said rotor support frame comprising an imperforate end member and a hub mounted in axially spaced relation on said support shaft means and a skeleton structure connecting said end member and hub with an annulus of water pickup material surrounding said skeleton structure, and said clutch elements comprising axially resilient means on the shaft engaging cooperating formations on said hub.

12. In the humidifier assembly defined in claim 11, said skeleton structure comprising rods extending from axially open sockets on said end member to radially open sockets on said hub, and external surfaces of said hub sockets providing said clutch formations.

13. In the humidifier assembly defined in claim 12, said axially resilient clutch means comprising a resilient arm fixed on said support shaft means by means holding the arm stressed between the shaft and the rotor support frame hub.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,640,515 med Feb. 8, 1972 Inventor(s) Walter Stiles It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 4, line 28, change "6" to --7--.

Signed and sealed this b th day of July 1972.

(SEAL) Attest R0 BERT GOTT S CHALK Attesting Officer FORM po'wso ("L691 iJSCOMM-DC 60376-5 69 t U,$, GOVERNMENT PRNTING OFFICE 1 I959 0-365-334 

1. In a humidifier assembly of the type wherein a rotatable water pickup rotor drum comprising a support frame and a porous annulus mounted thereon has a lower portion extending into means containing a body of water, rotor support shaft means mounted for rotation about an axis, means rotatably mounting opposite ends of said rotor support frame on said support shaft means so that said rotor drum may be bodily rotated upon and around said support shaft means, drive means comprising an electric motor and reduction gearing having an output shaft distinct from said support shaft means connected for rotating said support shaft means, aNd slip clutch means interconnecting said support shaft means and rotor support frame for normal rotation together comprising cooperating directly engaged clutch elements on the rotor support frame and support shaft means respectively, said clutch elements being so constructed and arranged as to slip to interrupt normal drive engagement when torque between the support shaft means and rotor support frame exerted in either direction exceeds a predetermined amount and to automatically assume normal drive engagement when said torque is less than said predetermined amount.
 2. In the humidifier assembly defined in claim 1, said shafts being connected by axially separable positive coupling means.
 3. In the humidifier assembly defined in claim 1, said output shaft being connected to one end of said support shaft means, and said slip clutch means connecting said rotor support frame to the other end of said support shaft means.
 4. In the humidifier assembly defined in claim 1, said rotor support frame comprising at one end a hub structure having a plurality of circumferentially spaced clutch formations providing the clutch element on said rotor support frame, and the clutch element on said support shaft means comprising a spring arm assembly nonrotatably secured on the support shaft means and having clutch formations coacting with those on the rotor support frame.
 5. In the humidifier assembly defined in claim 4, said spring arm assembly consisting essentially of resilient metal strip means having rounded clutch formations projecting into engagement with the rotor support frame hub.
 6. In the humidifier assembly defined in claim 1, said clutch elements being respectively a hub on the rotor support frame and a resiliently biased clutch part on the support shaft means engaging said hub.
 7. In the humidifier assembly defined in claim 6, said hub having a plurality of circumferentially spaced lateral projections and said clutch part having laterally projecting teeth frictionally engaging the hub between an adjacent pair of said projections.
 8. In the humidifier assembly defined in claim 6, said clutch part being a spring arm nonrotatably mounted on the support shaft means and having its opposite ends bent to form said hub engaging teeth.
 9. In the humidifier assembly defined in claim 1, said rotor support frame having a hub rotatably surrounding said support shaft means, circumferentially spaced lateral formations on said hub providing one of said clutch elements, and the other of said clutch elements being a spring arm fixed to said support shaft means and having opposite end projections frictionally engaging said hub between said formations.
 10. In the humidifier assembly defined in claim 9, said formations being rounded and said arm projections having rounded ends engaging the hub.
 11. In the humidifier assembly defined in claim 1, said rotor support frame comprising an imperforate end member and a hub mounted in axially spaced relation on said support shaft means and a skeleton structure connecting said end member and hub with an annulus of water pickup material surrounding said skeleton structure, and said clutch elements comprising axially resilient means on the shaft engaging cooperating formations on said hub.
 12. In the humidifier assembly defined in claim 11, said skeleton structure comprising rods extending from axially open sockets on said end member to radially open sockets on said hub, and external surfaces of said hub sockets providing said clutch formations.
 13. In the humidifier assembly defined in claim 12, said axially resilient clutch means comprising a resilient arm fixed on said support shaft means by means holding the arm stressed between the shaft and the rotor support frame hub. 